The sudden swelling of the auricle is usually due to the following reasons: 1. auricular pseudocysts: often auricular pseudocysts occur, and the cysts may be caused by the stimulation of the auricular area by rubbing or some mechanical injury factors. 2, auricular chondromyelitis: some patients may have acute purulent auricular chondromyelitis, with sudden onset of swelling and pain in the auricular area, which is often associated with trauma or crush injury to the auricular area, and may also be associated with secondary infection from frostbite to the auricle.